Ultrasonic classification of imperfect interfaces

Nagy, Péter B.

doi:10.1007/bf00566404

Cited by 241 publications

(154 citation statements)

References 27 publications

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“…A IMHz ultrasonic transducer, in an experimental set-up similar to that shown in Figure I, was used to measure the variation of graphite-graphite reflection coefficient with contact pressure. The results exhibited the expected frequency dependence of reflection coefficient and so the reflection coefficients were converted to stiffnesses via the spring model using Equation (1). Figure 6 shows the variation of graphite-graphite interfacial stiffness with contact pressure.…”

Section: Graphite-graphite Contact Apparatus and Experimental Resultsmentioning

confidence: 96%

“…Edited by Thompson and Chimenti, Kluwer Academic/Plenum Publishers, 1999 (1) where, K, is the stiffness of the interface, (J) is the angular frequency and subscripts 1 and 2 refer to the top and bottom media respectively. From Equation (1) it can be seen that the reflection coefficient is frequency dependent.…”

Section: Review O/progress In Quantitalive Nondestructive Evaluationmentioning

confidence: 99%

“…The ultrasonic reflection, and transmission, coefficients can be used to determine the extent of interfacial imperfections such as solid-solid contacts, in which two dry, solid bodies are loaded against one another [1]. This paper describes the results of studies of the interaction of ultrasound with three different solid-solid contact systems.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Use of Ultrasound to Investigate Rough Surface Contact Phenomena

Drinkwater

Dwyer-Joyce

Robinson

1999

Review of Progress in Quantitative Nondestructive Evaluation

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Section: Graphite-graphite Contact Apparatus and Experimental Resultsmentioning

confidence: 96%

Section: Review O/progress In Quantitalive Nondestructive Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Use of Ultrasound to Investigate Rough Surface Contact Phenomena

Drinkwater

Dwyer-Joyce

Robinson

1999

Review of Progress in Quantitative Nondestructive Evaluation

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“…Xiao and Nagy [1998] employed thermal stresses induced by a laser source to vary the closure of a surface-breaking crack which was simultaneously insonified by a high frequency Rayleigh wave. By means of suitable signal processing of the backscattered ultrasonic pulse acquired during different phases of the thermal modulation, these authors showed that the acoustic signature of the crack can be extracted from the noisy environment (see also [Nagy 1992]). In other words, the modulation technique was shown to be able to selectively detect nonlinear material defects.…”

Section: Numerical Resultsmentioning

confidence: 99%

So… is this a surface-breaking crack?

Poznić

Pecorari

2006

JOMMS

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An inspection technique used to assess the structural integrity of critical components in a nuclear power plant must be able to discern surface-breaking cracks from subsurface cracks. This work proposes an ultrasonic method to provide that information and presents a theoretical investigation into it. The main assumption of the model is that water carried by pressurized pipes infiltrates and fills a surface-breaking crack, while a subsurface crack is dry. The model simulates an inspection in which the modulation technique is employed and the surface hosting the crack is not accessible. A ratio, R, constructed with signals recorded in backscattering configuration during a modulation cycle, is examined and shown to provide a clear criterion allowing subsurface cracks to be distinguished from surface-breaking cracks when a shear vertical wave at 45 degree incidence is employed as a probe.

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“…It enables us to obtain the explicit connections between the permeable layer model and the open fracture model, which is discussed in a later section. Considering the quasi-static approximation (Nagy, 1992), the layer compliance can be represented as…”

Section: Theory Of Tube-wave Generationmentioning

confidence: 99%

Tube-wave Generation Due to Permeable Layers in a VSP Experiment - A New Model Elucidating the Effect of Dip Angles

Minato

Ghose

2017

Proceedings

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The hydraulic properties of subsurface fractures are critically important in the exploration of geothermal and hydrocarbon reservoirs. The analysis of tube waves (low-frequency Stoneley waves propagating along a fluid-filled borehole) is a promising approach to estimate the hydraulic properties of fractures intersecting a borehole. We present a new model for tube-wave generation in a borehole (VSP) by a permeable structure characterized by certain values of porosity and permeability. Contrary to the conventional theory, the new model accounts for the layer stiffness in the deformation process and it is valid for the large tube-wave amplitude. For the first time, it was possible to show a clear connection between the permeable-layer model and the parallel-wall open fracture model developed earlier. The generated tube-wave amplitudes well correspond to those of the multiple open fractures. Furthermore, the effect of large dip angles is extensively discussed. The approximate solution (the Mathieu functions) and the numerical modeling results (FEM) reveal that the effect of the dip angle is significant for a thick structure and large dip angles. The developed theory is important to evaluate field data which contain the effects of tube waves due to dipping, permeable layers, e.g., cataclasite layers and fault gouges.

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Ultrasonic classification of imperfect interfaces

Cited by 241 publications

References 27 publications

The Use of Ultrasound to Investigate Rough Surface Contact Phenomena

The Use of Ultrasound to Investigate Rough Surface Contact Phenomena

So… is this a surface-breaking crack?

Tube-wave Generation Due to Permeable Layers in a VSP Experiment - A New Model Elucidating the Effect of Dip Angles

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